1. In the iron extraction, is the elemental iron used by the body at all? I always have taught my kids that iron needs to be in the chelated form to be absorbed.

2. I also do a lab with anthocyanin indicators I found the basics of it in Stephen Thompson book "chemtrek"), not just red cabbage. I think it 's a great way to point out to kids that many substances are used from plants ( we use berries, spices, teas, flower petals, beets, etc.), including litmus.I have them use the different indicators to determine the range for the indicator, and then decide which indicator is the best for a titration. We have even used vanilla, which works as an indicator by smell.

3. I like the calcium in tums activity, because my students do have a block when it comes to atoms and ions and their different properties.

The other testing we do is using the luminol reaction as an indicator for anti-oxidants in food (vitamin C, E, selenium, etc.). I had the chance to work with a local university in developing this protocol and the kids really like it. One version of the lab just studies the dimming of the reaction qualitatively, but for the higher level students we use a spec 20 that we have taken the light blub out of. we read the amount of light given off by the original reaction and then compare the light given off by the reaction after adding an antioxidant. I had kids study green tea, juices, differences in canned versus fresh versus frozen vegetables, even chocolate. (That however, did not produce a huge antoxidant effect - to my great sadness!!!!!)